Paper bags are normally manufactured by forming a sheet of paper or paper composite into a tube. These tubes are processed and initially handled while in an essentially flat, collapsed condition. The tubes are stored, packaged or shipped in stacks of multiple quantities thereof. Heretofore, it was necessary to manually align and "square-up" the stacks of collapsed tubes before the stacks were delivered to storage or subsequent production operations.
The present invention consists of a method and apparatus which not only aligns the tubes in each stack but also allows automated transfer of the aligned stacks to preselected stacking locations on a pallet or the like.
According to the present invention, a multi-section endless conveyor accumulates a preselected quantity of the collapsed tubes into a roughly aligned stack thereof and transports them into an inclined, tray-like receptacle which is mounted for multi-directional movement. The receptacle is gradually rotated 180.degree. and rapidly reciprocated during rotation to vibrate the stack. The combined effects of gravity and vibration urge the tubes to shift relative to each other into engagement with adjacent sidewalls of the receptacle to align the stack. As the stack is rotated and vibrated, the receptacle revolves horizontally from a loading station adjacent the conveyor to a discharge station adjacent an automatically shiftable pallet system. The pallet system may be selectively operated to shift a pallet surface adjacent the discharge station between a plurality of preselected positions to provide indexed placement of the aligned stacks on the pallet surface.